Screen runs slowly after update to 5.3 untethered

Hi there, Have a ATV2 that was tethered 5.3 now iT is 5.3 untethered but first it ran super good, but now super slow. The films in mash-up, or 1channel Icefilms running slow. Anyone have an idea to fix it.

install the seatbelt Fix and try again

Thank for the update, but I’m really new with this. Could you explain were I can find this seatbelt Fix.

Thanks a lot